The group was brought ashore at the local port and has been transferred to the Curtin Detention Centre.

Department figures show 759 Vietnamese people have arrived by boat so far this year - up from fewer than 50 last year.

The Refugee Action Coalition's Ian Rintoul says it is a result of a Vietnamese government crackdown on dissidents and religious minorities.

"I guess I'm a little surprised, but it has been pretty obvious over the past couple of months that there have been increases in the number of people from Vietnam," he said.

"[That is] the result of the crackdown, on the underground Catholic Church in particular, in Vietnam."

Tri Vo, the president of the Vietnamese Community in Sydney, says he has no doubts about why they are fleeing.

"It's most probably due to the increase in the oppression and suppression of the people in Vietnam and the recent crackdown of the human rights activists, bloggers, media people and young people who are not afraid of speaking up, who demand democracy," he told The World Today.

But interviewed on Channel Ten last night, Dr Natalegawa clearly said he did not support the plan to tow back boats.

"Such a policy would constitute a unilateral type of measure that we do not support, and that's why in my earlier remarks today what I said basically is that let's hear what the policy is all about," he said.

"We are not ecstatic about it for sure, but in terms of in the spirit of wanting to hear the various policy options countries are proposing, parties are proposing, it's good to have this dialogue."